Transaction in Own Shares

GlaxoSmithKline PLC
27 March 2007


GlaxoSmithKline plc (the "Company") announces that in accordance with the 
authority granted by shareholders at the Company's Annual General Meeting on 17 
May 2006 it purchased 3,500,000 of its Ordinary shares of 25 pence each 
("shares") on 27 March 2007 at a price of 1381.0283 pence per share.

The Company intends to hold these shares in Treasury.

Following the purchase of these shares, the Company holds 276,082,678 of its 
shares in Treasury.

The Company has 5,734,236,296 shares in issue (excluding Treasury shares). This 
number represents the total voting rights in the Company and may be used by 
shareholders as the denominator for the calculations by which they can determine 
if they are required to notify their interest in, or a change to their interest 
in the Company under the Financial Services Authority's Disclosure and 
Transparency Rules.

This announcement does not constitute, or form part of, an offer or any
solicitation of an offer to purchase or subscribe for securities in any
jurisdiction and is in conformity with the Transparency Directive's transitional 
provision 6.



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